102 research outputs found
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Preference, performance, and chemical defense in an endangered butterfly using novel and ancestral host plants
Adoption of novel host plants by herbivorous insects can require new adaptations and may entail loss of adaptation to ancestral hosts. We examined relationships between an endangered subspecies of the butterfly Euphydryas editha (Taylor’s checkerspot) and three host plant species. Two of the hosts (Castilleja hispida, Castilleja levisecta) were used ancestrally while the other, Plantago lanceolata, is exotic and was adopted more recently. We measured oviposition preference, neonate preference, larval growth, and secondary chemical uptake on all three hosts. Adult females readily laid eggs on all hosts but favored Plantago and tended to avoid C. levisecta. Oviposition preference changed over time. Neonates had no preference among host species, but consistently chose bracts over leaves within both Castilleja species. Larvae developed successfully on all species and grew to similar size on all of them unless they ate only Castilleja leaves (rather than bracts) which limited their growth. Diet strongly influenced secondary chemical uptake by larvae. Larvae that ate Plantago or C. hispida leaves contained the highest concentrations of iridoid glycosides, and iridoid glycoside composition varied with host species and tissue type. Despite having largely switched to a novel exotic host and generally performing better on it, this population has retained breadth in preference and ability to use other hosts.
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Sustained IL-6/STAT-3 signaling in cholangiocarcinoma cells due to SOCS-3 epigenetic silencing.
BACKGROUND & AIMS: Interleukin 6 (IL-6)-mediated signal transducers and activators of transcription 3 (STAT-3) phosphorylation (activation) is aberrantly sustained in cholangiocarcinoma cells resulting in enhanced myeloid cell leukemia 1 (Mcl-1) expression and resistance to apoptosis. Because suppressor of cytokine signaling 3 (SOCS) controls the IL-6/STAT-3 signaling pathway by a classic feedback loop, the aims of this study were to examine SOCS-3 regulation in human cholangiocarcinoma.
METHODS: SOCS-3 expression was assessed in human cholangiocarcinoma tissue and the Mz-ChA-1 and CCLP1 human cholangiocarcinoma cell lines.
RESULTS: An inverse correlation was observed between phospho-STAT-3 and SOCS-3 protein expression in cholangiocarcinoma. In those cancers failing to express SOCS-3, extensive methylation of the SOCS-3 promoter was demonstrated in tumor but not in paired nontumor tissue. Likewise, methylation of the socs-3 promoter was also identified in 2 cholangiocarcinoma cell lines. Treatment with a demethylating agent, 5-aza-2\u27-deoxycytidine (DAC), restored IL-6 induction of SOCS-3, terminated the phospho-STAT-3 response, and reduced cellular levels of Mcl-1. Enforced expression of SOCS-3 also reduced IL-6 induction of phospho-STAT-3 and Mcl-1. Either DAC treatment or enforced SOCS-3 expression sensitized the cells to TRAIL-mediated apoptosis.
CONCLUSIONS: SOCS-3 epigenetic silencing is responsible for sustained IL-6/STAT-3 signaling and enhanced Mcl-1 expression in cholangiocarcinoma
Применение метода LSA-алгоритма для осуществления интеллектуального поиска комплекса упражнений развития компетенций
BACKGROUND & AIMS: Interleukin 6 (IL-6)-mediated signal transducers and activators of transcription 3 (STAT-3) phosphorylation (activation) is aberrantly sustained in cholangiocarcinoma cells resulting in enhanced myeloid cell leukemia 1 (Mcl-1) expression and resistance to apoptosis. Because suppressor of cytokine signaling 3 (SOCS) controls the IL-6/STAT-3 signaling pathway by a classic feedback loop, the aims of this study were to examine SOCS-3 regulation in human cholangiocarcinoma. METHODS: SOCS-3 expression was assessed in human cholangiocarcinoma tissue and the Mz-ChA-1 and CCLP1 human cholangiocarcinoma cell lines. RESULTS: An inverse correlation was observed between phospho-STAT-3 and SOCS-3 protein expression in cholangiocarcinoma. In those cancers failing to express SOCS-3, extensive methylation of the SOCS-3 promoter was demonstrated in tumor but not in paired nontumor tissue. Likewise, methylation of the socs-3 promoter was also identified in 2 cholangiocarcinoma cell lines. Treatment with a demethylating agent, 5-aza-2'-deoxycytidine (DAC), restored IL-6 induction of SOCS-3, terminated the phospho-STAT-3 response, and reduced cellular levels of Mcl-1. Enforced expression of SOCS-3 also reduced IL-6 induction of phospho-STAT-3 and Mcl-1. Either DAC treatment or enforced SOCS-3 expression sensitized the cells to TRAIL-mediated apoptosis. CONCLUSIONS: SOCS-3 epigenetic silencing is responsible for sustained IL-6/STAT-3 signaling and enhanced Mcl-1 expression in cholangiocarcinoma
CMB-S4 Science Book, First Edition
This book lays out the scientific goals to be addressed by the
next-generation ground-based cosmic microwave background experiment, CMB-S4,
envisioned to consist of dedicated telescopes at the South Pole, the high
Chilean Atacama plateau and possibly a northern hemisphere site, all equipped
with new superconducting cameras. CMB-S4 will dramatically advance cosmological
studies by crossing critical thresholds in the search for the B-mode
polarization signature of primordial gravitational waves, in the determination
of the number and masses of the neutrinos, in the search for evidence of new
light relics, in constraining the nature of dark energy, and in testing general
relativity on large scales
A genome-wide association study identifies new loci for factor VII and implicates factor VII in ischemic stroke etiology
Serum Amyloid A Stimulates Vascular and Renal Dysfunction in Apolipoprotein E-Deficient Mice Fed a Normal Chow Diet
Elevated serum amyloid A (SAA) levels may promote endothelial dysfunction, which is linked to cardiovascular and renal pathologies. We investigated the effect of SAA on vascular and renal function in apolipoprotein E-deficient (ApoE−/−) mice. Male ApoE−/− mice received vehicle (control), low-level lipopolysaccharide (LPS), or recombinant human SAA by i.p. injection every third day for 2 weeks. Heart, aorta and kidney were harvested between 3 days and 18 weeks after treatment. SAA administration increased vascular cell adhesion molecule (VCAM)-1 expression and circulating monocyte chemotactic protein (MCP)-1 and decreased aortic cyclic guanosine monophosphate (cGMP), consistent with SAA inhibiting nitric oxide bioactivity. In addition, binding of labeled leukocytes to excised aorta increased as monitored using an ex vivo leukocyte adhesion assay. Renal injury was evident 4 weeks after commencement of SAA treatment, manifesting as increased plasma urea, urinary protein, oxidized lipids, urinary kidney injury molecule (KIM)-1 and multiple cytokines and chemokines in kidney tissue, relative to controls. Phosphorylation of nuclear-factor-kappa-beta (NFκB-p-P65), tissue factor (TF), and macrophage recruitment increased in kidneys from ApoE−/− mice 4 weeks after SAA treatment, confirming that SAA elicited a pro-inflammatory and pro-thrombotic phenotype. These data indicate that SAA impairs endothelial and renal function in ApoE−/− mice in the absence of a high-fat diet
Discovery of novel heart rate-associated loci using the Exome Chip
Resting heart rate is a heritable trait, and an increase in heart rate is associated with increased mortality risk. Genome-wide association study analyses have found loci associated with resting heart rate, at the time of our study these loci explained 0.9% of the variation. This study aims to discover new genetic loci associated with heart rate from Exome Chip meta-analyses.
Heart rate was measured from either elecrtrocardiograms or pulse recordings. We meta-analysed heart rate association results from 104 452 European-ancestry individuals from 30 cohorts, genotyped using the Exome Chip. Twenty-four variants were selected for follow-up in an independent dataset (UK Biobank, N = 134 251). Conditional and gene-based testing was undertaken, and variants were investigated with bioinformatics methods.
We discovered five novel heart rate loci, and one new independent low-frequency non-synonymous variant in an established heart rate locus (KIAA1755). Lead variants in four of the novel loci are non-synonymous variants in the genes C10orf71, DALDR3, TESK2 and SEC31B. The variant at SEC31B is significantly associated with SEC31B expression in heart and tibial nerve tissue. Further candidate genes were detected from long-range regulatory chromatin interactions in heart tissue (SCD, SLF2 and MAPK8). We observed significant enrichment in DNase I hypersensitive sites in fetal heart and lung. Moreover, enrichment was seen for the first time in human neuronal progenitor cells (derived from embryonic stem cells) and fetal muscle samples by including our novel variants.
Our findings advance the knowledge of the genetic architecture of heart rate, and indicate new candidate genes for follow-up functional studies
CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
CMB-S4---the next-generation ground-based cosmic microwave background (CMB)
experiment---is set to significantly advance the sensitivity of CMB
measurements and enhance our understanding of the origin and evolution of the
Universe, from the highest energies at the dawn of time through the growth of
structure to the present day. Among the science cases pursued with CMB-S4, the
quest for detecting primordial gravitational waves is a central driver of the
experimental design. This work details the development of a forecasting
framework that includes a power-spectrum-based semi-analytic projection tool,
targeted explicitly towards optimizing constraints on the tensor-to-scalar
ratio, , in the presence of Galactic foregrounds and gravitational lensing
of the CMB. This framework is unique in its direct use of information from the
achieved performance of current Stage 2--3 CMB experiments to robustly forecast
the science reach of upcoming CMB-polarization endeavors. The methodology
allows for rapid iteration over experimental configurations and offers a
flexible way to optimize the design of future experiments given a desired
scientific goal. To form a closed-loop process, we couple this semi-analytic
tool with map-based validation studies, which allow for the injection of
additional complexity and verification of our forecasts with several
independent analysis methods. We document multiple rounds of forecasts for
CMB-S4 using this process and the resulting establishment of the current
reference design of the primordial gravitational-wave component of the Stage-4
experiment, optimized to achieve our science goals of detecting primordial
gravitational waves for at greater than , or, in the
absence of a detection, of reaching an upper limit of at CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note:
text overlap with arXiv:1907.0447
Impact of electrical contacts design and materials on the stability of Ti superconducting transition shape
The South Pole Telescope SPT-3G camera utilizes Ti/Au transition edge sensors (TESs). A key requirement for these sensors is reproducibility and long-term stability of the superconducting (SC) transitions. Here, we discuss the impact of electrical contacts design and materials on the shape of the SC transitions. Using scanning electron microscope, atomic force microscope, and optical differential interference contrast microscopy, we observed the presence of unexpected defects of morphological nature on the titanium surface and their evolution in time in proximity to Nb contacts. We found direct correlation between the variations of the morphology and the SC transition shape. Experiments with different diffusion barriers between TES and Nb leads were performed to clarify the origin of this problem. We have demonstrated that the reproducibility of superconducting transitions can be significantly improved by preventing diffusion processes in the TES–leads contact areas
Performance and characterization of the SPT-3G digital frequency-domain multiplexed readout system using an improved noise and crosstalk model
The third-generation South Pole Telescope camera (SPT-3G) improves upon its predecessor (SPTpol) by an order of magnitude increase in detectors on the focal plane. The technology used to read out and control these detectors, digital frequency-domain multiplexing (DfMUX), is conceptually the same as used for SPTpol, but extended to accommodate more detectors. A nearly 5× expansion in the readout operating bandwidth has enabled the use of this large focal plane, and SPT-3G performance meets the forecasting targets relevant to its science objectives. However, the electrical dynamics of the higher-bandwidth readout differ from predictions based on models of the SPTpol system due to the higher frequencies used and parasitic impedances associated with new cryogenic electronic architecture. To address this, we present an updated derivation for electrical crosstalk in higher-bandwidth DfMUX systems and identify two previously uncharacterized contributions to readout noise, which become dominant at high bias frequency. The updated crosstalk and noise models successfully describe the measured crosstalk and readout noise performance of SPT-3G. These results also suggest specific changes to warm electronics component values, wire-harness properties, and SQUID parameters, to improve the readout system for future experiments using DfMUX, such as the LiteBIRD space telescope
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